MNGSX
20+ Year Contributor
- 2,538
- 25
- Mar 30, 2003
-
Bloomington,
Minnesota
http://www.miata.net/garage/tirecalc.html
265 40 17 speedo is only of .1% or 1/10th of 1mph.
Very close OD match with stock. .4mm bigger radius
265 35 18 is a DEAD ON OD match. Nearly no speedo error at all.
a .1 mm smaller radius
Every brand and model is slightly different both would not affect the speedo enough to care about.
Now lets compare the amount of side wall on stock AWD tires to DG's
215-55-16 118.3 mm
275-40-17 110 mm
The width more than makes up for the cushion effect lost by the 8mm of sidewall decrease. A 275 wide by 110mm cushion vs a 215 wide by 118 mm.
What I want to run
265-40-17 106 mm sidewall
I might even run these with light wheels.
265-35-18 92.8mm sidewall A little thin but not nearly as bad as some rice boy sizes.
like a celica
http://www.sportcompactcarweb.com/projectcars/0010scc_projcelica/
They are running
215-40-17
only 86mm of sidewall.
That is a 40 aspect 17 in rim vs a 35 apect 18 and the 18 still has more sidewall due to the width
265 40 17 speedo is only of .1% or 1/10th of 1mph.
Very close OD match with stock. .4mm bigger radius
265 35 18 is a DEAD ON OD match. Nearly no speedo error at all.
a .1 mm smaller radius
Every brand and model is slightly different both would not affect the speedo enough to care about.
Now lets compare the amount of side wall on stock AWD tires to DG's
215-55-16 118.3 mm
275-40-17 110 mm
The width more than makes up for the cushion effect lost by the 8mm of sidewall decrease. A 275 wide by 110mm cushion vs a 215 wide by 118 mm.
What I want to run
265-40-17 106 mm sidewall
I might even run these with light wheels.
265-35-18 92.8mm sidewall A little thin but not nearly as bad as some rice boy sizes.
like a celica
http://www.sportcompactcarweb.com/projectcars/0010scc_projcelica/
They are running
215-40-17
only 86mm of sidewall.
That is a 40 aspect 17 in rim vs a 35 apect 18 and the 18 still has more sidewall due to the width